Current cellular telecommunication systems employ mechanisms that enable a mobile user to be authorised to use services provided within his or her home network. Certain mechanisms that authorise network access in home and visited networks are also known by a man skilled in the art.
However, current solutions are lacking in that a generic, service-based mechanism is however needed to authorise the use of services offered by a network to visiting subscribers. Such a mechanism would need to obtain certain subscriber attributes from the home network in order to perform authorisation. This authorisation can be only partially provided by existing mechanisms such as AAA, or VPLMN access attributes defined in the GSM/GPRS HLR.
The 3GPP standards define various control mechanisms and parameters (e.g. in 3GPP TS 23.060) that are stored within an HLR (Home Location Register) dictating whether a subscriber may utilise visited network services, and what charging characteristics (e.g. normal, prepaid, flat-rate, and/or hot billing subscription) apply to the subscriber or PDP context. These known mechanisms however are bearer specific and do not support per-service charging well. In particular, these known mechanisms do not support on a per-service basis for a given subscriber determination of service authorisation, charging method or charging system address.
Further, certain authentication protocols such as RADIUS and Diameter are typically used for network access authorisation. Adapting them for performing service-based authorisation would require the use of non-standard extensions to the protocol; thereby not offering a standardised solution.
Current solutions do not provide a generic mechanism that would allow a visiting subscriber to use a specific service, resolve how the subscriber should be charged, and would resolve the charging server or the balance server to which credit control messages should be directed.